Method for detecting a degradation of a switching device having an electromagnetic actuator

Abstract

A method is proposed for detecting a degradation of a switching device (30) comprising an electromagnetic actuator (1) configured to unlock a control mechanism (4) comprising an elastic element (7), the method comprising the steps: (i) controlling the electromagnetic actuator (1), (ii) measuring a current (C) flowing in the electromagnetic actuator (1), (iii) determining from the measured current (C) a reaction time (ta) of the electromagnetic actuator (1), (iv) determining from the measured current (C) a quantity (i1) representative of the current flowing in the electromagnetic actuator (1), (v) determining a parameter (P) in the form of a polynomial of the determined reaction time (ta) and the determined quantity (i1) representative of the current flowing in the electromagnetic actuator (1),(vi) iterate steps (i) to (v) for a set of successive commands of the electromagnetic actuator (1) so as to obtain a set (E) of values ​​of the determined parameter (P), (vii) determine a degradation of the electromagnetic actuator (1) from the evolution of the values ​​of the set (E) during the successive commands of the electromagnetic actuator (1).

Description

technical field

[0001] The present invention relates to the field of switching devices for electrical equipment, for example, for low and medium voltage electrical equipment. The switching device may, for example, be a circuit breaker. Previous technique

[0002] A low- or medium-voltage switching device may include one or more electromagnetic actuators that unlock a spring-loaded control mechanism, thereby moving a movable electrical contact to open or close an electrical circuit. In the case of a circuit breaker, the electrical circuit is opened when a fault occurs. The fault may be, for example, a short circuit between two phases, or between a phase and earth. Closing the circuit allows a load to be energized.

[0003] The electromagnetic actuator comprises a movable magnetic core and a control coil. Under the influence of an electric current flowing through the control coil, the magnetic core moves. The magnetic core is mechanically coupled to the control mechanism, which acts on the movable electrical contacts to open or close the electrical circuit.

[0004] To ensure the safety of the electrical grid and people, it is important to be able to verify the proper functioning of switching devices throughout their lifespan. For this purpose, circuit breakers can include measuring circuits that allow for real-time diagnosis of the electromagnetic actuator's condition. This electromagnetic actuator is generally subject to the effects of aging, which can progressively degrade its electrical or mechanical functions, eventually rendering it inoperative. It is therefore important for users to be able to monitor the electromagnetic actuator's condition. Ideally, users should be able to intervene to repair or replace the electromagnetic actuator at an appropriate time during the electrical grid's operation.

[0005] Document US7692522 describes a method according to the preamble of claim 1. Summary

[0006] To this end, the invention proposes a method for detecting a degradation of a switching device comprising an electromagnetic actuator configured to unlock a control mechanism comprising an elastic element configured to move a movable electrical contact so as to open or close an electrical circuit, the method comprising the steps: (i) control the electromagnetic actuator, (ii) measure a current flowing through the electromagnetic actuator when the electromagnetic actuator is controlled, (iii) determine a reaction time of the electromagnetic actuator from the measured current, (iv) determine a quantity representative of the current flowing through the electromagnetic actuator when the electromagnetic actuator is controlled from the measured current, (v) determine a parameter in the form of a polynomial of the determined reaction time and the determined quantity representative of the current flowing through the electromagnetic actuator when the electromagnetic actuator is controlled, (vi) iterate steps (i) to (v) for a series of successive control operations of the electromagnetic actuator so as to obtain a set of values ​​for the determined parameter,(vii) determine the degradation of the electromagnetic actuator from the evolution of the assembly values ​​during successive commands of the electromagnetic actuator.

[0007] The method for detecting switching device degradation is a method for detecting changes in the switching device's behavior due to the aging of its components. Component aging includes, for example, wear, deformation, the effects of corrosion, changes in magnetic performance, and changes in the tribological properties of the components. When the electromagnetic actuator is operating nominally, the values ​​of the assembly do not change significantly during successive actuations. In other words, the various values ​​of the assembly remain essentially constant. Conversely, progressive degradation of the electromagnetic actuator tends to cause changes in values ​​during successive actuations, specifically a fluctuation in these values. The values ​​of the assembly are no longer essentially constant and exhibit significant fluctuation.This gradual evolution allows for the detection of degradation in the magnetic actuator of the switching device. The method for detecting degradation in the switching device also allows for the anticipation of a fault in the switching device. Indeed, uncorrected degradation of the switching device can eventually lead to a fault.

[0008] The features listed in the following paragraphs can be implemented independently of each other or in any technically possible combination:

[0009] At step (vii), the evolution of the values ​​of the assembly can be a fluctuation of the values ​​of the assembly during successive commands of the electromagnetic actuator.

[0010] The set of values ​​of the polynomial of the determined reaction time and the determined quantity is obtained by a succession of consecutive commands of the electromagnetic actuator of the switching device.

[0011] Each value in the set of values ​​of the polynomial of the determined reaction time and the determined quantity corresponds to a distinct actuation of the electromagnetic actuator of the switching device.

[0012] The switching device can be a circuit breaker.

[0013] Alternatively, the switching device can be a switch.

[0014] According to another variant, the switching device can be a disconnector.

[0015] The switching device includes: a movable electrical contact between an opening position of an electrical circuit and a closing position of the electrical circuit, a control mechanism comprising: -- an elastic element configured to move the electrical contact from the closing position to the opening position or from the opening position to the closing position, so as to respectively open or close the electrical circuit, -- a release element configured to move from a locking position in which the elastic element is held in a tensioned state to a release position in which the elastic element is free to relax so as to move the electrical contact from the closing position to the opening position or from the opening position to the closing position, an electromagnetic actuator configured to move the release element from the locking position to the release position.

[0016] According to one embodiment, called the first embodiment: - the elastic element is configured to move the electrical contact from the closed position to the open position so as to open the electrical circuit, and - the unlocking element is configured to move from a locking position in which the elastic element is held in a state of tension to a release position in which the elastic element is free to relax so as to move the electrical contact from the closed position to the open position.

[0017] According to another embodiment, called the second embodiment: - The elastic element is configured to move the electrical contact from the open position to the closed position, so as to close the electrical circuit, - The unlocking element is configured to move from a locking position in which the elastic element is held in a state of tension to a release position in which the elastic element is free to relax so as to move the electrical contact from the open position to the closed position.

[0018] The elastic element is configured to apply a driving force to the moving electrical contact. The elastic element is connected to a drive element configured to move the moving electrical contact in order to open or close an electrical circuit. The drive element includes, for example, a connecting rod.

[0019] According to the first embodiment, the unlocking member can move from a locked position in which the elastic member of the control mechanism is elastically constrained and in which the moving electrical contact is in the position of closing the electrical circuit, to an unlocked position in which the elastic member of the control mechanism is released and moves the moving electrical contact from the position of closing the electrical circuit to a position of opening the electrical circuit.

[0020] According to the second embodiment, the unlocking member can move from a locked position in which the elastic member of the control mechanism is elastically constrained and in which the moving electrical contact is in the opening position of the electrical circuit, to an unlocked position in which the elastic member of the control mechanism is released and moves the moving electrical contact from an opening position of the electrical circuit to the closing position of the electrical circuit.

[0021] Unlocking the control mechanism means releasing the elastic element of the control mechanism. In other words, unlocking the control mechanism is equivalent to moving the unlocking element from the locked position to the released position.

[0022] The electromagnetic actuator is an electromagnet.

[0023] The electromagnetic actuator includes a control coil and a magnetic core configured to move under the action of a magnetic field created by an electric current flowing through the control coil.

[0024] The magnetic core, for example, is mobile in translation.

[0025] THE The magnetic core is mechanically coupled to a release mechanism configured to move from a locking position in which the elastic element is held in a state of tension to a release position in which the elastic element is free to relax so as to move the electrical contact from the closed position to the open position.

[0026] Measuring a current flowing in the electromagnetic actuator means measuring the intensity of the electric current flowing in the electromagnetic actuator.

[0027] The current flowing through the electromagnetic actuator is detected by an electronic measuring circuit.

[0028] The current flowing through the electromagnetic actuator is sampled, for example with a sampling frequency between 1 kHz and 100 kHz.

[0029] The electromagnetic actuator includes a coupling element that mechanically couples the magnetic core to the unlocking mechanism.

[0030] The control mechanism may include rotating moving parts.

[0031] The control mechanism may include moving parts that translate.

[0032] The elastic element can be a spring, for example a spiral spring or a helical spring.

[0033] The electromagnetic actuator is configured to trigger the movement of the moving electrical contact in order to open the electrical circuit. When the switching device is a circuit breaker, the electromagnetic actuator is configured to trigger the opening of the electrical circuit in the event of a fault in the electrical circuit.

[0034] According to one aspect of the proposed detection method, the reaction time of the electromagnetic actuator is determined from the time variations of the measured current.

[0035] The proposed method therefore does not require the installation of any additional sensors, such as a sensor for the displacement of the electrical contact or a sensor for the displacement of an element of the control mechanism.

[0036] The proposed method includes a sub-step for determining the temporal variations of the measured current.

[0037] According to an example of the implementation of the detection method, the reaction time of the electromagnetic actuator is equal to a time elapsed between an instant of the start of the flow of electric current in the electromagnetic actuator and an instant corresponding to a local minimum value of the electric current flowing in the electromagnetic actuator.

[0038] According to one embodiment of the detection method, the representative quantity of the current flowing in the electromagnetic actuator when the switching device is actuation is a local maximum value of the electric current flowing in the electromagnetic actuator.

[0039] In step (v), the parameter is determined by a polynomial in two indeterminates, that is, a sum of monomials in two indeterminates. The first indeterminate is the determined reaction time, and the second indeterminate is the determined quantity representing the current flowing through the electromagnetic actuator when the electromagnetic actuator is activated. Each monomial of the polynomial is thus determined by the product of: the determined reaction time, raised to a given first power, the determined quantity representing the current flowing through the electromagnetic actuator when the electromagnetic actuator is activated, raised to a given second power, and a constant coefficient. Each monomial can be written in the form: A i ∗ ta k i ∗ i 1 L i

[0040] The polynomial forming the parameter P can thus be written: P = ∑ i = 0 H A i ∗ ta k i ∗ i 1 L i with the coefficients k 0 , ..., k H taking rational values, the coefficients L 0 , ..., LH taking rational values, and the coefficients A i taking rational values.

[0041] Among a multitude of parameters studied, the applicant concluded that the polynomial formed from the reaction time of the electromagnetic actuator and the local maximum value of the circuit current in the electromagnetic actuator best describes a progressive degradation of this electromagnetic actuator. The polynomial is thus a polynomial with two indeterminates.

[0042] According to a particular embodiment of the proposed detection method, the parameter P is equal to the product of the determined reaction time and the determined quantity representing the current flowing in the electromagnetic actuator when the electromagnetic actuator is controlled.

[0043] In other words, in this particular case of implementation of the process, the polynomial comprises a single term, that is to say, it is a monomial. The first power of the monomial is equal to 1 and the second power of the monomial is also equal to 1. The resulting monomial is then equal to the product of the determined reaction time and the determined quantity representing the current flowing in the electromagnetic actuator when the electromagnetic actuator is controlled; that is to say, the result of multiplying the value of the determined reaction time by the value of the determined quantity representing the current flowing in the electromagnetic actuator when the electromagnetic actuator is controlled.

[0044] The local maximum value of the current is obtained for an instant between the start of the flow of electric current in the electromagnetic actuator and an instant corresponding to a local minimum of the electric current flowing in the electromagnetic actuator.

[0045] According to one embodiment, the detection process comprises the following substeps: calculate a value of a statistical parameter representative of a fluctuation in the values ​​of the set of values ​​of the polynomial of the determined reaction time and the determined quantity, determine a degradation of the electromagnetic actuator from the calculated value of the statistical parameter.

[0046] According to an example of the implementation of the detection method, the statistical parameter representing a fluctuation in the values ​​of the set of values ​​of the polynomial of the determined reaction time and the determined quantity comprises a difference between: a current value of the polynomial of the determined reaction time and the determined quantity, determined for a current actuation of the switching device, and an average value of the values ​​of the polynomial of the determined reaction time and the determined quantity obtained for a predetermined number of actuations preceding the current actuation of the switching device.

[0047] The average value can be a moving average calculated from the values ​​corresponding to the actuations preceding the current actuation, and comprising a number of values ​​equal to the predetermined number of actuations.

[0048] According to an example of implementation of the detection method, the statistical parameter representing a fluctuation in the values ​​of the set of values ​​of the determined reaction time polynomial and the determined quantity includes a standard deviation of the values ​​of the determined reaction time polynomial and the determined quantity determined for a set of actuations of the switching device carried out under reference conditions corresponding to a new state of the switching device.

[0049] The set of actuations of the switching device carried out under reference conditions includes, for example, 20 successive actuations of the switching device.

[0050] The proposed method thus includes a calibration phase to quantify the nominal variations in the value of the determined reaction time polynomial and the representative quantity of the current flowing in the electromagnetic actuator during the actuation of the switching device. These nominal variations correspond to the variations observed in a reference state in which the switching device exhibits neither manufacturing defects nor wear.

[0051] The reference state corresponds, for example, to a new state of the switching device.

[0052] The proposed method includes a measurement phase in which the variations in the value of the determined reaction time polynomial and the representative quantity of the current flowing in the electromagnetic actuator are analyzed.

[0053] The measurement phase follows the calibration phase.

[0054] The measurement phase is carried out throughout the entire period of use of the switching device.

[0055] According to one embodiment of the detection process, the statistical parameter representing a fluctuation of the polynomial of the determined reaction time and the determined quantity is equal to the ratio of: the difference between a current value of the polynomial determined for a current actuation and the average value of the polynomial values ​​obtained for a predetermined number of actuations preceding the current actuation, and the determined standard deviation of the polynomial values ​​of the determined reaction time and the determined quantity, determined for a set of actuations of the switching device carried out under reference conditions corresponding to a new state of the switching device.

[0056] The proposed statistical parameter enables robust detection of potential degradation of the electromagnetic actuator, while remaining simple to implement. In particular, the necessary calculations can be easily performed in real time, allowing for rapid detection of any degradation.

[0057] According to one embodiment of the detection process, the statistical parameter representing a fluctuation of the polynomial of the determined reaction time and the determined quantity is equal to: D i = P i − ∑ j = i − M − 1 j = i − 1 P j M ∑ j = 1 K P j − ∑ j = 1 j = K P j K K 2 With P i the determined value of the polynomial for an actuation of rank i, D i the calculated value of the statistical parameter for the actuation of rank i, M a number of actuations taken into account to determine an average value, K a number of actuations carried out under reference conditions corresponding to a new state of the switching device.

[0058] According to an example of implementation of the detection method, a degradation of the electromagnetic actuator is determined when the absolute value of the statistical parameter representing a fluctuation of the polynomial of the determined reaction time and the determined quantity is greater than a first predetermined positive threshold.

[0059] The value chosen for the first predetermined positive threshold allows the sensitivity of the proposed detection method to be adjusted.

[0060] The first predetermined positive threshold is, for example, between 2 and 3.

[0061] Conversely, an absence of degradation of the electromagnetic actuator is determined when the absolute value of the statistical parameter representing a fluctuation of the polynomial of the determined reaction time and the determined quantity is less than or equal to the first predetermined positive threshold.

[0062] In other words, degradation is determined when the absolute value of the statistical parameter exceeds a predefined threshold value. Conversely, the absence of degradation is determined when the absolute value of the statistical parameter falls below the predefined threshold value.

[0063] According to an example of an embodiment of the detection process, the degradation of the electromagnetic actuator is classified into a first type of degradation, called minor degradation, when the absolute value of the statistical parameter representing a fluctuation of the polynomial of the determined reaction time and the determined quantity is greater than a first predetermined positive threshold and less than a second predetermined positive threshold.

[0064] The second predetermined positive threshold is, for example, between 4 and 5.

[0065] According to an example of an embodiment of the detection process, the degradation of the electromagnetic actuator is classified into a second type of degradation, called major degradation, when the absolute value of the statistical parameter representing a fluctuation of the polynomial of the determined reaction time and the determined quantity is greater than the second predetermined positive threshold.

[0066] The statistical parameter used thus allows a quantification of the severity of the degradation, and not just the presence or absence of degradation.

[0067] The detection process may include a step of emitting an alert signal in response to a determination of degradation of the electromagnetic actuator.

[0068] The alert signal emitted allows users to plan and carry out maintenance or replacement of the switching device when it is in a degraded or defective state.

[0069] No warning signal is issued when no degradation has been detected. In other words, no alert is issued when the proposed method indicates that the electromagnetic actuator is free from degradation.

[0070] The invention also relates to a switching device comprising: an electromagnetic actuator configured to unlock a control mechanism comprising an elastic element configured to move an electrical contact so as to open or close an electrical circuit, an electronic control unit configured to implement the degradation detection method as described above.

[0071] According to one embodiment, the switching device comprises: a control circuit configured to flow an electric current through the electromagnetic actuator, a sensor to measure the current flowing through the electromagnetic actuator. Brief description of the drawings

[0072] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which: [ Fig. 1 ] is a schematic view of an electrical circuit equipped with a switching device, the electrical circuit being in the open position, [ Fig. 2 ] is a schematic view of an electrical circuit equipped with a switching device, the electrical circuit being in the closed position, [ Fig. 3 ] is a time evolution curve of the current in an electromagnetic actuator of a switching device, during its actuation, [ Fig. 4] represents the evolution of the curve of the figure 3 , during the aging of the switching device, [ Fig. 5 ] is a time-domain diagram illustrating the process according to the invention, [ Fig. 6 ] is a block diagram illustrating different stages of the process according to the invention. Description of the implementation methods :

[0073] To facilitate the reading of the figures, the different elements are not necessarily drawn to scale. In these figures, identical elements bear the same references. Some elements or parameters may be indexed, that is, designated, for example, as first element or second element, or first parameter and second parameter, etc. This indexing aims to differentiate similar, but not identical, elements or parameters. This indexing does not imply any priority of one element or parameter over another, and the designations can be interchanged. When it is specified that a subsystem contains a given element, this does not exclude the presence of other elements in that subsystem. Similarly, when it is specified that a subsystem includes a given element, it is understood that the subsystem includes at least that element.

[0074] We have schematically represented on the figure 1an electrical circuit 50. The electrical circuit 50 comprises three electrical conductors 20, 21, 22, each conductor corresponding to one phase of a medium voltage three-phase network.

[0075] The electrical circuit 50 includes a switching device 30. The switching device 30 may be a circuit breaker. In one variant, the switching device 30 may be a switch. In another application example, the switching device 30 may be a disconnect switch.

[0076] The switching device 30 comprises: an electromagnetic actuator 1 configured to unlock a control mechanism 4 comprising an elastic member 7 configured to move a movable electrical contact 10 so as to open or close an electrical circuit 50, an electronic control unit 25 configured to implement the degradation detection method which will be described in detail below.

[0077] The electromagnetic actuator 1 is an electromagnet. The electromagnetic actuator 1 comprises a control coil 2 and a magnetic core 3 configured to move under the action of a magnetic field created by an electric current flowing through the control coil 2.

[0078] The magnetic core 3 is, for example, translationally mobile. The magnetic core 3 is mechanically coupled to a release member 8 configured to move from a locking position V in which the elastic member 7 is held in a tension state to a release position L in which the elastic member 7 is free to relax so as to move the electrical contact 10 from the closed position F to the open position O.

[0079] The movable electrical contact 10 is associated with the electrical conductor 20. Similarly, a movable electrical contact 11 is associated with the electrical conductor 21, and a movable electrical contact 12 is associated with the electrical conductor 22. On the figure 1 The movable electrical contact 10 is shown in the open position, that is, in the position where the flow of electric current in the electrical circuit 50 is interrupted. On the figure 2 The movable electrical contact 10 is shown in the closed position, that is, in the position where the flow of electric current in the electrical circuit 50 is possible.

[0080] The electromagnetic actuator 1 includes a coupling element 13 that mechanically couples the magnetic core 3 to the unlocking member 8. The control mechanism 4 may include rotating moving parts. The control mechanism 4 may include translational moving parts. The control mechanism 4 can jointly move the three movable electrical contacts 10, 11, 12.

[0081] The electromagnetic actuator 1 is configured to trigger a movement of the movable electrical contact 10 in order to open the electrical circuit 50. When the switching device 30 is a circuit breaker, the electromagnetic actuator 1 is configured to trigger the opening of the electrical circuit 50 in the event of a fault on the electrical circuit 50. An example of a fault that may be present on the electrical circuit 50 is a short circuit between two separate phases. Another type of fault could be a short circuit between a phase and earth.

[0082] The switching device 30 includes: an electrical contact 10 movable between an open position O of an electrical circuit 50 and a closed position F of the electrical circuit 50, a control mechanism 4 comprising: -- an elastic element 7 configured to move the electrical contact 10 from the closed position F to the open position O or from the open position O to the closed position F, so as to respectively open or close the electrical circuit 50, -- a release element 8 configured to move from a locking position V in which the elastic element 7 is held in a tensioned state to a release position L in which the elastic element 7 is free to relax so as to move the electrical contact 10 from the closed position F to the open position O or from the open position O to the closed position F,an electromagnetic actuator 1 configured to move the unlocking member 8 from the locked position V to the released position L. ,

[0083] According to the embodiment illustrated on the figure 1 and the figure 2 : The elastic member 7 is configured to move the electrical contact 10 from the closed position F to the open position O so as to open the electrical circuit 50, and the unlocking member 8 is configured to move from a locking position V in which the elastic member 7 is held in a tensioned state to a release position L in which the elastic member 7 is free to relax so as to move the electrical contact 10 from the closed position F to the open position O. In other words, the control mechanism 4 allows the current to be cut off in the electrical circuit 50.

[0084] According to another embodiment, not shown: The elastic element 7 is configured to move the electrical contact 10 from the open position O to the closed position F, so as to close the electrical circuit 50, the unlocking element 8 is configured to move from a locking position V in which the elastic element 7 is held in a tension state to a release position L in which the elastic element 7 is free to relax so as to move the electrical contact 10 from the open position O to the closed position F. In other words, the control mechanism 4 in this case allows the current to flow in the electrical circuit 50.

[0085] The elastic element 7 is configured to apply a driving force to the movable electrical contact 10. The elastic element 7 can be a spring, for example, a spiral spring or a helical spring. The elastic element 7 is connected to a drive element 9 configured to move the movable electrical contact 10 so as to open or close an electrical circuit 50. The drive element 9 includes, for example, a connecting rod.

[0086] According to the embodiment illustrated on the figure 1 and the figure 2, the unlocking member 8 can move from a locked position in which the elastic member 7 of the control mechanism 4 is elastically constrained and in which the movable electrical contact 10 is in the closing position F of the electrical circuit 50, to an unlocked position V in which the elastic member 7 of the control mechanism 4 is released and moves the movable electrical contact 10 from the closing position F of the electrical circuit 50 to an opening position O of the electrical circuit 50.

[0087] According to the second embodiment, not illustrated, the unlocking member 8 can move from a locked position in which the elastic member 7 of the control mechanism 4 is elastically constrained and in which the movable electrical contact 10 is in the open position O of the electrical circuit 50, to an unlocked position V in which the elastic member 7 of the control mechanism 4 is released and moves the movable electrical contact 10 from an open position O of the electrical circuit 50 to the closed position F of the electrical circuit 50.

[0088] Unlocking the control mechanism 4 means releasing the elastic element 7 from the control mechanism 4. The electromagnet 1 controls the movement of the unlocking element 8 so as to release the elastic element 7.

[0089] The propulsive force for moving the movable electrical contact 10 is provided by the elastic element 7. The electromagnetic actuator 1 does not interact directly with the movable electrical contact 10. The electromagnetic actuator 1 provides an electromagnetic force that moves the unlocking element 8, via the coupling element 13. Once the unlocking element 8 is in the unlocked position V, the potential energy stored by the elastic element 7 is released and moves the electrical contact 10 via the drive element 9. On the figure 1 The unlocking member 8 is in the locked position V and the elastic member 7, schematically represented as a helical spring, is held in the compressed state. The movable contact 10 is in the closed position, corresponding to the flow of electric current in the electrical conductor 20. On the figure 2The coupling element 13 moved the unlocking member 8 to the release position. The elastic member 7 is in the relaxed state, and the drive element 9 moved the movable electrical contact 10 to its open position, corresponding to an interruption of the current flow in the electrical conductor 20 and therefore in the electrical circuit 50.

[0090] The mechanical components of the switching device 30 can degrade over its service life, due in particular to wear resulting from repeated tripping, deformation, and potential chemical corrosion. It is therefore desirable to have a diagnostic method for the switching device 30, that is, a method for detecting the onset of degradation in the switching device 30.

[0091] A method is thus proposed for detecting a degradation of a switching device 30 comprising an electromagnetic actuator 1 configured to unlock a control mechanism 4 comprising an elastic element 7 configured to move a movable electrical contact 10 so as to open or close an electrical circuit 50, the method comprising the steps: (i) control the electromagnetic actuator 1, (ii) measure a current C flowing through the electromagnetic actuator 1 when the electromagnetic actuator 1 is controlled, (iii) determine a reaction time ta of the electromagnetic actuator 1 from the measured current C, (iv) determine a quantity i1 representing the current flowing through the electromagnetic actuator 1 when the electromagnetic actuator 1 is controlled from the measured current C, (v) determine a parameter P in the form of a polynomial of the determined reaction time ta and the determined quantity i1 representing the current flowing through the electromagnetic actuator 1 when the electromagnetic actuator 1 is controlled, (vi) iterate steps (i) to (v) for a series of successive control operations of the electromagnetic actuator 1 so as to obtain a set E of values ​​of the determined parameter P,(vii) determine a degradation of the electromagnetic actuator 1 from the evolution of the values ​​of the assembly E during successive commands of the electromagnetic actuator 1.

[0092] When the electromagnetic actuator 1 is operating nominally, the values ​​of the E' assembly do not change significantly during successive actuations. In other words, the various values ​​of the E' assembly remain essentially constant. Conversely, a progressive degradation of the electromagnetic actuator 1 tends to cause the values ​​of the E' assembly to change during successive actuations. The values ​​of the E' assembly are no longer essentially constant and exhibit a significant change. This progressive change allows for the detection of a degradation of the switching device 30, as well as the presence of a fault.

[0093] The set E of values ​​of the polynomial P of the determined reaction time ta and of the determined quantity i1 is obtained by a succession of consecutive commands of the electromagnetic actuator 1 of the switching device 30.

[0094] Each value in the set E of values ​​of the polynomial P of the determined reaction time ta and the determined quantity i1 corresponds to a distinct actuation of the electromagnetic actuator 1 of the switching device 30. In other words, a value of the reaction time ta is associated with each of the different actuations of the switching device 30. Similarly, a value of the determined parameter i1 is associated with each of the different actuations of the switching device 30. A value of the polynomial P of ta and i1 is associated with each of the actuations of the switching device 30.

[0095] The switching device 30 comprises: a control circuit 5 configured to circulate an electric current in electromagnetic actuator 1, a sensor 6 for measuring the current flowing in electromagnetic actuator 1.

[0096] Measuring a current C flowing in the electromagnetic actuator 1 means measuring the intensity of the electric current flowing in the electromagnetic actuator 1. More precisely, the intensity of the electric current flowing in the control coil 2 is measured.

[0097] To achieve this, the current C flowing through the electromagnetic actuator 1 is detected by an electronic measuring circuit. In the illustrated example, the current C flowing through the electromagnetic actuator 1 is sampled, for example, with a sampling frequency between 1 kHz and 100 kHz. In other words, the current value is measured periodically during an actuation phase of the electromagnetic actuator 1.

[0098] The reaction time ta of the electromagnetic actuator 1 is determined from the time variations of the measured current C. The proposed method thus includes a substep for determining the time variations of the measured current C.

[0099] No sensor other than the current measurement sensor is required to determine the reaction time ta of the electromagnetic actuator 1. In particular, it is not necessary to have a displacement sensor of an element of the control mechanism 4 linking the movable electrical contact 10 to the electromagnetic actuator 1.

[0100] According to one aspect of the proposed detection method, the reaction time ta of the electromagnetic actuator 1 is equal to a time elapsed between an instant t0 of the start of the flow of electric current in the electromagnetic actuator 1 and an instant tmin corresponding to a local minimum value of the electric current flowing in the electromagnetic actuator 1.

[0101] There figure 3 This schematically represents a time-varying curve of the electric current flowing through the electromagnetic actuator 1 when it is activated. This current-time curve is designated by the symbol G1.

[0102] The curve G1 representing the time evolution of the electric current in the electromagnetic actuator 1 comprises a first, continuously increasing portion p1, a second, continuously decreasing portion p2, the second portion p2 following the first portion p1, a third, continuously increasing portion p3, the third portion p3 following the second portion p2. The instant tmin, corresponding to the local minimum of the current, is the instant separating the third portion p3 from the second portion p2. The instant t0, when the electric current begins flowing in the electromagnetic actuator 1, corresponds to the beginning of the continuously increasing portion p1. The first portion p1 includes an initial part in which the current increases linearly. Then, as t1 approaches, the increase in current slows down. At t1, the current reaches its maximum value since t0, and then the current decreases.This decrease in current is linked to the evolution of the air gap between the moving and fixed parts. The current decreases until time tmin, where it reaches its minimum value since time t1, then increases again.

[0103] The instant tmin corresponds to the end of the movement phase of the magnetic core 3. Once the air gap no longer evolves, the current begins to increase again, which corresponds to the portion p3 of the curve G1.

[0104] The time evolution curve of the electric current in the electromagnetic actuator 1 includes a fourth, substantially constant portion p4, the fourth portion P4 following the third portion p3. From the instant indicated by t2, the steady current establishes itself at a constant value i2. The current drop when the control of coil 2 is interrupted is not shown in the diagram. figure 3 .

[0105] According to one embodiment of the detection method, the quantity i1 representing the current flowing in the electromagnetic actuator 1 when the switching device 30 is a local maximum value of the electric current flowing in the electromagnetic actuator 1.

[0106] The parameter i1 corresponds to the maximum value of the current during the control phase during which the magnetic core 3 is in motion, which extends between the time t0 and the time tmin.

[0107] In step (v), the parameter P is determined by a sum of monomials with two indeterminates. The first indeterminate is the determined reaction time ta, and the second indeterminate is the determined quantity i1 representing the current flowing in the electromagnetic actuator 1 during the activation of the electromagnetic actuator 1. Thus, we have: P = ∑ i = 0 H M i Each monomial Mi of the polynomial is thus determined by the product of: the determined reaction time ta, raised to a first given power Ki, and: the determined quantity i1 representing the current flowing in the electromagnetic actuator 1 during the activation of the electromagnetic actuator 1, raised to a second given power Li, and a constant coefficient Ai. Each monomial Mi can be written in the form: M i = A i ∗ ta k i ∗ i 1 L i

[0108] The polynomial forming the parameter P can thus be written: P = ∑ i = 0 H A i ∗ ta k i ∗ i 1 L i with the coefficients k₀, ..., kH taking rational values, the coefficients L₀, ..., LH taking rational values, and the coefficients Aᵢ taking rational values. The polynomial used to determine the parameter P comprises, in its most general form, (H+1) monomials.

[0109] Among a multitude of parameters studied, the applicant concluded that the polynomial formed from the reaction time ta of the electromagnetic actuator 1 and the local maximum value i1 of the current in the electromagnetic actuator 1 is the quantity that best accounts for a progressive degradation of this electromagnetic actuator. The polynomial is a polynomial with two indeterminates, the first indeterminate being the quantity ta and the second indeterminate being the quantity i1.

[0110] According to a particular embodiment of the proposed detection method, the parameter P is equal to the product of the determined reaction time ta and the determined quantity i1 representing the current flowing in the electromagnetic actuator 1 when the electromagnetic actuator 1 is controlled.

[0111] In other words, in this particular case of implementation of the process, the polynomial P is a monomial, whose first power k 1 is equal to 1 and the second power L 1 is also equal to 1. The polynomial formed is then equal to the product of the determined reaction time ta and the determined quantity i1 representing the current flowing in the electromagnetic actuator 1 when the electromagnetic actuator 1 is controlled, that is to say, the result of the multiplication ta * i1 of the value of the determined reaction time ta by the value of the determined quantity i1 representing the current flowing in the electromagnetic actuator 1 when the electromagnetic actuator 1 is controlled.

[0112] The maximum local value i1 of the current is obtained for an instant t1 between an instant t0 of the start of circulation of the electric current in the electromagnetic actuator 1 and an instant tmin corresponding to a local minimum of the electric current circulating in the electromagnetic actuator 1. The maximum local value i1 of the current is the value of the current obtained at the passage from the first portion p1 to the second portion p2.

[0113] There figure 4 schematically represents the time evolution of the electric current flowing through the electromagnetic actuator 1 when it is activated, during an accelerated aging test of a switching device 30. In particular, the figure 4This illustrates the evolution of the parameters ta and i1 during this accelerated aging test. This type of test is carried out under more severe conditions compared to normal use of the switching device, with, for example, a higher temperature and a more corrosive atmosphere than in normal conditions.

[0114] Curve G2 represents the initial state at the start of the test, and curves G3, G4, ..., G7 represent the state after increasing test durations. The time tmin, corresponding to the end of the magnetic core 3's movement, gradually shifts towards increasingly higher values. The direction of this change is indicated by the arrow fe. This shift reflects the increasing difficulty in moving the mechanical parts of the switching device. On curve G7, the current is almost constant, indicating that the magnetic core is practically blocked in its movement. Such a state corresponds to a failure of the switching device.

[0115] According to one embodiment of the proposed process, the detection process comprises the following sub-steps: calculate a value of a statistical parameter D representative of a fluctuation of the values ​​of the set E of values ​​of the polynomial of the determined reaction time ta and of the determined parameter i1, determine a degradation of the electromagnetic actuator 1 from the calculated value of the statistical parameter D.

[0116] The evolution of the values ​​of set E during successive actuations is monitored quantitatively using the statistical parameter D.

[0117] The statistical parameter D representing a fluctuation in the values ​​of the set E of values ​​of the polynomial of the determined reaction time ta and of the determined quantity i1 includes a difference d between: a current value of the polynomial P of the determined reaction time ta and of the determined quantity i1, determined for a current actuation of the switching device 30, and an average value Moy of the values ​​of the polynomial P of the determined reaction time ta and of the determined quantity i1 obtained for a predetermined number M of actuations preceding the current actuation of the switching device 30.

[0118] The average value, Moy, can be a moving average calculated from the M values ​​corresponding to the M actuations preceding the current actuation, and comprising a number of values ​​equal to the predetermined number M of actuations. The current actuation is not included in the subset of values ​​considered for calculating the average value. This subset comprises M values.

[0119] According to an example of the detection method implementation, the statistical parameter D representing a fluctuation in the values ​​of the set E of values ​​of the polynomial of the determined reaction time ta and the determined quantity i1 comprises a standard deviation of the values ​​of the polynomial of the determined reaction time ta and the determined quantity i1 determined for a set of actuations of the switching device 30 carried out under reference conditions corresponding to a new state of the switching device 30. The standard deviation of a set of samples is understood to be the quantity equal to the square root of the variance of that set of samples. The variance itself is defined as the expected value of the square of the deviations from the mean, or the root mean square of the deviations between the values ​​of the set of samples and the mean of those values.

[0120] The set of actuations of the switching device 30 carried out under reference conditions includes, for example, 20 successive actuations of the switching device.

[0121] The proposed process thus includes a calibration phase allowing to quantify the nominal variations of the value of the reaction time polynomial determined ta and of the quantity i1 representing the current flowing in the electromagnetic actuator 1 during the actuation of the switching device 30. These nominal variations correspond to the variations observed in a reference state in which the switching device 30 shows no degradation.

[0122] The reference state corresponds, for example, to a new state of the switching device 30. A new state is defined as a period starting with the first actuation of the switching device, lasting for a predetermined maximum duration and comprising a predetermined maximum number of actuations. In other words, the new state corresponds to a time period.

[0123] The values ​​acquired under these reference conditions allow us to determine the nominal variability of the quantity equal to the polynomial of the determined reaction time ta and the determined quantity i1. This variability is characterized here by the mathematical quantity equal to the standard deviation of the quantity equal to the polynomial of the determined reaction time ta and the determined quantity i1, determined for the actuations corresponding to the calibration phase. This variability is characterized based on a predetermined number K of values ​​corresponding to a predetermined number of actuations. For example, K = 20 successive actuations performed in the new state of the switching device can be used to characterize the initial variability of the quantity used to determine a degradation of the switching device 30.

[0124] The proposed method includes a measurement phase in which variations in the value of the determined reaction time polynomial ta and in the quantity i1 representing the current flowing in the electromagnetic actuator 1 are analyzed. The measurement phase follows the calibration phase. For example, the measurement phase is carried out throughout the operating time of the switching device 30.

[0125] There figure 5 This illustrates the values ​​of the quantity P, equal to the polynomial of the determined reaction time ta, and of the determined quantity i1, for different actuations. Part A schematically represents the measurements taken at a first instant t1. Part B of the figure schematically represents the measurements taken at a second instant t2, which is later than t1.

[0126] The measurement points enclosed within the frame designated by J0 are those taken under reference conditions corresponding to a new state of the switching device 30. To simplify the figure, only 7 measurement points are shown. It can be observed that the dispersion of the values ​​of the quantity P is small. The symbol Ec0 denotes the standard deviation of the values ​​corresponding to the set of actuations of the switching device 30 performed under reference conditions and taken into account for the calibration phase. In the example shown, the values ​​taken into account for determining the reference standard deviation correspond to consecutive actuations of the electromagnetic actuator 1. It is also possible that the values ​​do not correspond to consecutive actuations; that is, some actuations may not be taken into account.

[0127] On part A of the figure 5The measurement points enclosed within the frame designated J1 are the points used at time t1 for the measurement phase. As before, to simplify the figure, only 10 measurement points for the quantity P are shown. The value Pn, determined at time t1, is the current value at time t1, that is, the most recent value, corresponding to the most recent command of the electromagnetic actuator 1. The horizontal dashed line indicates the average value amoy1 of the values ​​taken into account, that is, those present within frame J1. The arrow designated d1 illustrates the difference d1 between the current value Pn and the average value amoy1 calculated using the example of the figure 5 on the 10 measurement points preceding the current measurement.

[0128] On part B of the figure 5The measurement points enclosed within the frame designated J2 are the points used at time t2 for the measurement phase. As before, 10 measurement points are used in the figure. The value determined at time t2 is the current value at time t2, that is, the most recent value. Compared to time t1, 4 new measurements have been acquired, and the 4 oldest values ​​in frame J1 are not used at time t2 and are not part of frame J2. The horizontal dashed line indicates the average value avg2 of the values ​​taken into account, that is, those present in frame J2. The arrow designated d2 illustrates the difference d2 between the current value Pn+4 and the average value avg2.

[0129] According to one embodiment of the detection process, the statistical parameter D representing a fluctuation of the polynomial of the determined reaction time ta and of the determined quantity i1 is equal to the ratio of: the difference d between a current value of the polynomial P determined for a current actuation and the average value Moy of the values ​​of the polynomial P obtained for a predetermined number M of actuations preceding the current actuation, and of the determined standard deviation of the values ​​of the polynomial of the determined reaction time ta and of the determined quantity i1, determined for a set of actuations of the switching device 30 carried out under reference conditions corresponding to a new state of the switching device 30.

[0130] The proposed statistical parameter D enables robust detection of degradation in the electromagnetic actuator 1, while remaining simple to implement. In particular, the necessary calculations can easily be performed in real time, thus allowing for real-time detection of the presence of degradation.

[0131] The statistical parameter D representing a fluctuation of the polynomial of the determined reaction time ta and of the determined quantity i1 is thus equal, for a measurement of rank i, to: D i = P i − ∑ j = i − M − 1 j = i − 1 P j M ∑ j = 1 K P j − ∑ j = 1 j = K P j K K 2

[0132] With Pi the determined value of the polynomial P for an actuation of rank i, Di the calculated value of the statistical parameter D for the actuation of rank i, M the number of actuations taken into account for determining the average value, and K the number of actuations performed under reference conditions corresponding to a new state of the switching device 30. That is to say, K is the number of actuations taken into account for the initial calibration.

[0133] A degradation of the electromagnetic actuator 1 is determined when the absolute value of the statistical parameter D, representing a fluctuation in the polynomial of the determined reaction time ta and the determined quantity i1, exceeds a first predetermined positive threshold S1. By definition, the absolute value of a given number is its numerical value regardless of its sign. If a number is positive, its absolute value is thus equal to that number. If a number is negative, its absolute value is equal to the opposite of that number.

[0134] We say that degradation is determined when degradation is detected.

[0135] The value chosen for the first predetermined positive threshold S1 allows for adjusting the sensitivity of the proposed detection method. For example, the first predetermined positive threshold S1 is between 2 and 3. The closer the chosen threshold is to 1, the more sensitive the defect detection will be; that is, a small deviation from the reference conditions will be interpreted as the onset of degradation.

[0136] Conversely, an absence of degradation of the electromagnetic actuator 1 is determined when the absolute value of the statistical parameter D representing a fluctuation of the polynomial of the determined reaction time ta and of the determined quantity i1 is less than or equal to the first predetermined positive threshold S1.

[0137] A low absolute value for the statistical parameter D, indicating a small difference between the current behavior of the electromagnetic actuator 1 and its behavior when new, indicates an operating state close to the new state. An absence of degradation can thus be confirmed.

[0138] According to an example embodiment of the detection method, the degradation of the electromagnetic actuator 1 is classified into a first type of degradation, called minor degradation, when the absolute value of the statistical parameter D representing a fluctuation of the polynomial of the determined reaction time ta and of the determined quantity i1 is greater than a first predetermined positive threshold S1 and less than a second predetermined positive threshold S2. The second predetermined positive threshold S2 is for example between 4 and 5.

[0139] According to an example of an embodiment of the detection process, the degradation of the electromagnetic actuator 1 is classified into a second type of degradation, called major degradation, when the absolute value of the statistical parameter D representing a fluctuation of the polynomial of the determined reaction time ta and of the determined quantity i1 is greater than the second predetermined positive threshold S2.

[0140] It should be noted that the proposed method can be implemented without directly calculating the absolute value of the statistical parameter D. Indeed, the determined value of the statistical parameter D can be compared, on the one hand, to the positive threshold values ​​S1 and S2, and on the other hand, to the opposite values ​​-S1 and -S2 of these threshold values. Any degradation can then be determined based on this dual comparison.

[0141] The statistical parameter D used thus allows for a quantification of the severity of the degradation, and not simply a determination of its presence or absence. Operators of the electrical circuit 50 on which the switching device is used can therefore monitor the device's performance over time and react accordingly.

[0142] The detection method may include a step of emitting an alert signal in response to a determination of degradation of the electromagnetic actuator 1.

[0143] The warning signal can be, for example, a code stored in an electronic control unit. Alternatively, or in addition, the warning signal can be an indicator light.

[0144] Alternatively, or in addition, the alert signal can be a message displayed on a control screen. Other types of alerts are, of course, possible. The alert signal issued may differ depending on whether the detected degradation is minor or major.

[0145] The alert signal issued allows users to plan and carry out maintenance or replacement of the degraded switching device, in order to correct the diagnosed problem.

[0146] No warning signal is issued when no degradation has been detected. In other words, no alert is issued when the proposed method indicates that the electromagnetic actuator 1 is free from degradation.

Claims

1. Method for detecting a degradation of a switching device (30) comprising an electromagnetic actuator (1) configured to unlock a control mechanism (4) comprising an elastic member (7) configured to move a movable electrical contact (10) so as to open or close an electrical circuit (50), the method comprising the steps of: (i) commanding the electromagnetic actuator (1), (ii) measuring a current (C) circulating in the electromagnetic actuator (1) during the command of the electromagnetic actuator (1), characterised by (iii) determining from the measured current (C) a reaction time (ta) of the electromagnetic actuator (1), (iv) determining from the measured current (C) a quantity (i1) representative of the current circulating in the electromagnetic actuator (1) during the command of the electromagnetic actuator (1), (v) determining a parameter (P) in the form of a polynomial of the determined reaction time (ta) and of the determined quantity (i1) representative of the current circulating in the electromagnetic actuator (1) during the command of the electromagnetic actuator (1), the parameter (P) being written: P = ∑ i = 0 H A i ∗ ta K i ∗ i 1 L i with: the coefficients k0, ..., kH taking rational values, the coefficients L0, ..., LH taking rational values, and the coefficients Ai taking rational values, (vi) iterating the steps (i) to (v) for a set of successive commands of the electromagnetic actuator (1) so as to obtain a set (E) of values of the determined parameter (P), (vii) determining a degradation of the electromagnetic actuator (1) from the evolution of the values of the set (E) in the course of the successive commands of the electromagnetic actuator (1).

2. Detection method according to claim 1, wherein the switching device (30) comprises: - an electrical contact (10) movable between a position for opening (O) an electrical circuit (50) and a position for closing (F) the electrical circuit (50), - a control mechanism (4) comprising: -- an elastic member (7) configured to move the electrical contact (10) from the closing position (F) to the opening position (O) or from the opening position (O) to the closing position (F), so as to respectively open or close the electrical circuit (50), -- an unlocking member (8) configured to pass from a locking position (V) wherein the elastic member (7) is kept in a state of tension to a freeing position (L) wherein the elastic member (7) is free to relax so as to move the electrical contact (10) from the closing position (F) to the opening position (O) or from the opening position (O) to the closing position (F), - an electromagnetic actuator (1) configured to move the unlocking member (8) from the locking position (V) to the freeing position (L).

3. Detection method according to claim 1 or 2, wherein the parameter (P) is equal to the product of the determined reaction time (ta) and of the determined quantity (i1) representative of the current circulating in the electromagnetic actuator (1) during the command of the electromagnetic actuator (1).

4. Detection method according to one of the preceding claims, wherein the reaction time (ta) of the electromagnetic actuator (1) is determined from the time variations of the measured current (C).

5. Detection method according to one of the preceding claims, wherein the reaction time (ta) of the electromagnetic actuator is equal to a time elapsed between an instant (t0) of start of circulation of the electrical current in the electromagnetic actuator (1) and an instant (tmin) corresponding to a local minimum value of the electrical current circulating in the electromagnetic actuator (1).

6. Detection method according to one of the preceding claims, wherein the quantity (i1) representative of the current circulating in the electromagnetic actuator (1) during the actuation of the switching device (30) is a local maximum value of the electrical current circulating in the electromagnetic actuator (1).

7. Detection method according to one of the preceding claims, comprising the substeps of: - calculating a value of a statistical parameter (D) representative of a fluctuation of the values of the set (E) of values of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (i1), - determining a degradation of the electromagnetic actuator (1) from the calculated value of the statistical parameter (D).

8. Detection method according to the preceding claim, wherein the statistical parameter (D) representative of a fluctuation of the values of the set (E) of values of the polynomial of the determined reaction time (ta) and of the determined quantity (i1) comprises a difference (d) between: - a current value of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (i1), determined for a current actuation of the switching device (30), and - an average value (Moy) of the values of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (i1) obtained for a predetermined number (M) of actuations preceding the current actuation of the switching device (30).

9. Detection method according to claim 7 or 8, wherein the statistical parameter (D) representative of a fluctuation of the values of the set (E) of values of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (i1) comprises a standard deviation of the values of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (i1), determined for a set of actuations of the switching device (30) carried out under reference conditions corresponding to a new condition of the switching device (30).

10. Detection method according to one of claims 7 to 9, wherein the statistical parameter (D) representative of a fluctuation of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (i1) is equal to the ratio of: - the difference (d) between a current value of the polynomial (P) determined for a current actuation and the average value (Moy) of the values of the polynomial (P) obtained for a predetermined number (M) of actuations preceding the current actuation, and - the determined standard deviation of the values of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (i1) determined for a set of actuations of the switching device (30) carried out under reference conditions corresponding to a new condition of the switching device (30).

11. Detection method according to one of claims 7 to 10, wherein the statistical parameter (D) representative of a fluctuation of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (i1) is equal to: D i = P i − ∑ j = i − M − 1 j = i − 1 P j M ∑ j = 1 K P j − ∑ j = 1 j = K P j K K 2 With Pi the determined value of the polynomial (P) for an actuation of rank i, Di the calculated value of the statistical parameter (D) for the actuation of rank i, M a number of actuations taken into account in order to determine an average value, K a number of actuations carried out under reference conditions corresponding to a new condition of the switching device (30).

12. Detection method according to one of claims 7 to 11, wherein a degradation of the electromagnetic actuator (1) is determined when the absolute value of the statistical parameter (D) representative of a fluctuation of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (i1) is above a first positive predetermined threshold (S1).

13. Detection method according to the preceding claim, wherein the degradation of the electromagnetic actuator (1) is classified as a first type of degradation, referred to as minor degradation, when the absolute value of the statistical parameter (D) representative of a fluctuation of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (i1) is above a first positive predetermined threshold (S1) and below a second positive predetermined threshold (S2).

14. Detection method according to claim 12 or 13, wherein the degradation of the electromagnetic actuator (1) is classified as a second type of fault, referred to as major degradation, when the absolute value of the statistical parameter (D) representative of a fluctuation of the polynomial (P) of the determined reaction time (ta) and of the determined quantity (i1) is above the second positive predetermined threshold (S2).

15. Detection method according to one of the preceding claims, comprising a step of transmitting an alarm signal in response to a determination of a degradation of the electromagnetic actuator (1).

16. Switching device (30) including: - an electromagnetic actuator (1) configured to unlock a control mechanism (4) comprising an elastic member (7) configured to move a movable electrical contact (10) so as to open or close an electrical circuit (50), - an electronic control unit (15) configured to implement the method for detecting degradation according to one of the preceding claims, wherein the switching device (30) is a circuit breaker, or a switch, or a disconnector.

Images